Turbine engines including gear assemblies to provide a speed or direction change at a fan assembly generally require a narrow range of stiffness for a supporting structure. Sufficiently soft or low stiffness supporting structures are generally necessary to mitigate load transfer from the fan assembly to the gear assembly. However, insufficiently stiff supporting structures enable undesired vibratory modes at the gear assembly. Additionally, the supporting structure may generally provide dampening or vibratory isolation between the gear assembly and the surrounding engine. However, such desired vibratory isolation varies based on the frequency of vibration, such as due to engine operating condition.
As such, there is a need for a support structure that provides a desired magnitude of stiffness across various engine conditions.